By Alecia Reid

PHILADELPHIA (CBS) — Missing children have been rescued from danger thanks to Operation Safeguard. Authorities located the children during an investigation into human trafficking.

More than a dozen critically missing children in and around Philadelphia are safe thanks to a federal cavalry coming to their aid, a recovery and rescue mission consisting of the U.S. Marshall’s Office, the Department of Human Services in partnership with a slew of other agencies.

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Operation Safeguard was a month-long project aimed at recovering 26 critically missing children.

“It was challenging,” Robert Clark, a supervisory deputy with the Fugitive Task Force in Philadelphia, said.

Between Feb. 15 and March 15, the U.S. Marshall’s Office successfully located and recovered a total of 16 children between the ages of 13 and 17 years old.

“You go home at night feeling good that we were able to help a child,” Clark said.

In order to be considered critically missing, there had to be an element of danger — whether it be medical, mental health conditions, or sex trafficking. Investigators believe at least a half-dozen of them were being trafficked.

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“Upon recovery, out of those six, four we still have open investigations for child sex trafficking,” Clark said.

Clark said these were some of the most at-risk and challenging recovery cases in the area.

“They may have been a runaway, but they had a previous history of being sexually exploited,” Clark said, “so we wanted to make sure that we were able to find that kid and take them off the street before they were able to be exploited again.”

Child advocate Naomi Studevan says youngsters need support to help prevent them from running away in the first place.

“They need someone outside of the home to hear them, to see them, to validate them, to support them,” Studevan said. “They need that socialization of friends and fun and get a chance to let their hair down.”

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Funding for the month-long program came from federal funds that have now been exhausted, but the U.S. Marshall’s Office says this mission of safeguarding children is critical. They will look for local sources of funding to keep it going.